Rotor



J. M. BARR 3 Sheets-Sh` est 1 May 26 1925. 1,539,232

J. M. BARR ROTOR Original Filed Feb. 18. 1922 3 Sheets-Sheet 2 Tja/'673%LOZI? Larr.

May 26, 1925.

Original Filed Feb. 18. 1922 1,539,232 J. M. BARR ROTOR 3 Sheets-Sheet 3Hmmm! Q maker-a sheet metal and mayl after the win Patented May 26,1925.

UNITED STATES lPAriaNT O'FFicE.

JOHN iu. BARR, or

CONSIN.

mILwAoigilsE, wIscONsIN,l LOUIS ALLI's COMPANY, or MILWAUKEE,

ASSIGNOR, BY MESNE ASSIGNMENTS, T0 VISCOITSIIT,v A COBYOBIATION OF WIS-BOTOX.

has itscore provided with a winding having integral conductors andendrings.

This winding ordinarily is made from b e-made vfrom a single piece orseveralpieces or sections joined together. v

Among the objects of the invention is to provide a yrotor with a windingwhich may be readily and economically lmanufactured and applied, whichis eicient, .strong and durable, and which is firmly 'retained Ainplace.

According to the way the inventionhas ordinarily been practiced, a flatsheet metal winding is first formed, and then this winding is formedinto a cylinder.

The winding in cylindrical form may bemade in various ways.

The cylindrical winding is.. the core in a position to have its lacedupon ongitudinal conductors register with the axial or longrtudinalslots in the core, and then the end rings are perimetrically contractedvto bring the conductors 'in therein.

The end rin s may be ioined before or ing in cylindrical form is appliedto the core. 'The perimetric contraction of the end rings increases thetensile stren th thereof.

The end rings `by the tensi e strength thereof hold the conductors inplace.

The end rings may, of course, be contracted perimetrically before-thewinding is applied to the-core.

The basic invention disclosed herein is claimed in my copendinapplication Serial No. 605,228, tiled Decem er 6, 1922. The views oftlie drawings are:'

Figure 1 is a" plan of a blank'from which the winding is made.

Fig. 2 is a plan of the blank, with the longitudnal conductors formed atan vangle to the plane of the blank.

Fig. 3 is a perspective of the winding Adinal conductors.

elevation' oa rotor. with `thespiral longitudinal conductors enteringthe winding of rings, a portion of the slots and hold them med Februaryis, i922, serial Ne. 531,554. Renewed lingue: 2o, i924.

`formed into a cylinder with theends joined together to form end rin s.

Fig. 4 sliowsthe cylindliical winding with the end rings'of differentdiameters.

Fig. 5 is an end elevation of. a rotor with the cylindrical .winding ofFig. 4 .applied thereto, the longitudinal conductors-being disposedpartially within the rotor slots.

Fig. 6 isa perspective'of the rotor with the -winding thereofrin finalposition.'

Figff vis a perspective'of a' continuous winding having spit-allyarranged longitu- Fig. 8 is an end the rotor slots.

Fig. 9is a perspective of the rotor .with Fig. 8 in final positionthereon.

Fig. 10 is a section through one of the end which -is substantiallyinclosed by a circular `n iagnetic ring ofv substantially U- haped-crosssection.

Fig. 11 is al section through one of the end ringssubstantiallyvinclosed by a` circular magnetic ring of substantiallyU-'shaped cross section. v

Fig. 12 is a top lan of apparatus 'or'v contracting the cylindrical:winding onto a rotor.

Fig. 13 is a side elevation, partly in sectioxi, of the apparatus shownin Fig..12.

' Fig. 14 is a vertical section through'one of the radial plungers online 1 4-14 of Fig. 12. Fig. 15 is a view on line 15 -15'Of Fig. Fig. 16isa top' plan of one of the radial plungers.

Fig. 17 is an end elevation of one of the radial plungers. l

A'blank 1 of -sheet copper or other suitable -conducting material hasthe margins thereof bent to forni double edges, and' this maybe donebefore or after tlie conductors are formed. l

The blank 1 is men provided with spaced holes Shear each folded edge,and with slits 4 joining opposite holes 3.

formed by thefolded over e ges'.

The ormedblank (Fig. 2) is then formed i into a cylinder (Fig. 3) andthe edges of the core to which the winding is to be applied.'

end conducting members 2'brazed,- welded or otherwise joined togethertofor1 n continu.

ous end rings of the winding.

The vinside diameter of the winding within the longitudinal conductors5` is slightly greater than the diameter of the slotted rotor One of the'end rings 2 (Fig. 4) may be contracted so that the diameter of thewinding inside the longitudinal conductors ad]acent the 'end rings ofsmaller diameter is less than the diameter of the rotor core.

The cylindrical winding (Fig. 4) is now read to be a plied to the rotorcore.

Wlienapp yin the winding to the rotor core, the end o the winding havingthe "larger diametern'is placed over one end of the rotor core, and isthrust into placev with the longitudinal conductorsinthe rotor slots.and the endrings 2' spaced from the ends of the'rotor core. 4 v v lThewinding isthen contracted perimetrically and radially to force theconductorsv inwardlly into final position in the slots.

This perimetric contraction may be accomplished by swaging or otherwiseapplying .pressure radially to the end rings, whereby the end rings arecontracted perimetrically to bring the conductors in the slots andholdthem therein.

The end rin smay be contracted one at a time or simu taneously byapplying pressure radially thereto' from without'the end rings.

One form of apparatus for contracting the end ringswil later.- t

The winding in i-,ts `final position onv the rotor is shown inFi 6.

The contractionfo the e'nd rings shortens the' perimeter'and increasesthe crosssectional area of'the rings. thus increasing'the conductivitythereof.

Thev perimetric contraction of the end be described not only reduces thediameter thereofbut increases the thickness, hardness and tensilestrength of the metal thereof.

The shortened end rings hold the conductors securely in place againstradial displace- `ment by the tensile strength thereof.`

Fivures 7 to 9 show a squirrel cage winding raving spirally disposedlongitudinal conductors applied to a spirallyslotted rotor core b radialcontraction `of the winding as a W iole.4

The blank is' punched and slittcd andthe longitudinal conductors bent atan angle to `the plane of the blank in a manner similar to thatpreviously-described.

The windin is then formed into a cylinder as shown 1n Fig. 7, the endsof the end conducting members being welded or otherwise rigidly fastenedtogether toI form continuous end rings.

- conductors into perimetrically i :inthe external diameter of the rotorcore,

so that the windin'g may be applied to the core by thrusting thelspiral'lon itudinal the'longitudinal spiral rotor slots.

After the winding has been so positioned with respect to the slots ofthe core as shown' in Fig.. 8,-tlle end rings are perimetricallycontracted to bring the conductors ihto final position in the slots andhold them therein.

Fig-9 shows the winding of Fig. 7 in its final position on the'rotorcore. i

Any of the described methods of inserting tlie longitudinal conductorsin the rotorwinding having either straight or spirally disposed f.longitudinal applied to a slotted rotor core.

10 and 11 show the end rings pro-I vide with inclosing magnetic ringsforincreasing the starting torque of an induction motor. The folded overportion 26 of each end ring 2, in Fig. 10, is substantially inclosed bya circular magnetic ring 27 of substantially U-shaped cross section,while, in Fig. 11, the entire end ring 2 is substantially inclosed b acircular magnetic ring 28 of substantia ly U-shaped cross section. Whenstartingv the motor, the frequency of the current in the rotor windingis substantially that of the source of current and the magnetic rings 27and 28 inclosing the end rings increase the apparent resistance of thewinding. As the speed of the rotor increases the apparent resistancedecreases, for the frequency` of the rotor or secondary currentdecreases as the slip decreases. So when the motor is operating at speedwith but a small amount of slip, the apparent'resistance of thesecondary winding issubstantially equal to the ohmic' resistancethereof.

The magnetic rin 27 and 28 stitfen the slbts may, of course, be employedwhen a -end rings of the Win ing so that during contraction thereof theydo not bulge but re-l main substantially cylindrical.

The rings 27 and 28 may be made of ma.- terial such `as nickel steelalloy,'which is i magnetic below a certain critical temperature, butwhich at suchtem erature loses its magnetic property and comes non.

magnetic.`

These rings made of such material arc es ecially advantageous. inincreasing the e ciency of an induction motor when operating under load.Due to the relatively large amounts of currents in the end rings 2 underheavy loads, the magnetic rings heat up to abovethe critical temperatureand' become non-magnetic, thereby eliminating the choking action thereofupon the conductors is tol be currents in the end rings. Thus theeffective conductivity of the end rings is increased,

vand the induction motor operates with less crease the conductivity of.the end rings when the inclosing rings become nou-niag- .netic. If theinclosing rings 27 and 28 are spot welded to the end rings2 and 26, asindicated at 29 and 30, or otherwise in good electrical contacttherewith, the inclosing.

rings, when becoming non-magnetic due to increase'in temperature to thecritical value, assist rather than repel the flow of current in the endrings and actually become effective as conductors.

Figs. 1-2 to. 17 show contracting apparatus for perimet-ricallycontracting the end rings of the winding to bring the Aconductorsthereof in final position in the core slots and hold them therein.

The contracting apparatus comprises inner4 and louter concentric rings10 and 11 which are relatively movable axially.

The inner ring carries radially disposed plungers 12 whichare movedinwardly by the `outer ring whenever either ring is moved axial-lytoward the other.

The inner ring 10, which may lbe considered the movablering, is providedwith radially disposed guideways 13 in which the plungers 12 aremounted.

These guideways 13 may be formed with milling radial slotsin the ring 10and covering the open side thereof by an annular plate 14 fastened tothe ring 10 by screws 14 or other fastening means.

The outer or stationary ring 11 has an inclined inner periphery 15 whichserves as a track on which the outer ends of the plungers 12 slide asthe inner ring is forced down into the outer ring.

ln'order that the concentric relation be tween the spaced inner andouter rings may be maintained, a plurality of inwardly'e'xtendingcentering lugs 16 are fastened tto the outer ring 11 by screws 17 orother fasteningmeans. l

'l` he outer 'end of each plunger 12 is beveled so as to co-operate withthe inclined track 15.

Each plunger is bifurcated from its head or inner end for more thanone-half of its length, so the two parts 18 and 19 of the bifurcatedinner end may yield toward each othei; as the plungers are forced towardthe center.

' The inner ends of the plungers are pro- `vided with concave surfacesso as to fit the are to be contract The outer edge of the plunger headpart 18 is provided with tongues,20 and grooves 21 which are arranged tomesh with alternately Vdisposed grooves 22"' and tongues 23 cylindricalend rings of the windings which provided in the outer edge 19 of theadjacent plunger.

lV-henever` an end ring ofa winding is to be contracted, the inner i'ing10 of the contracting apparatus is raised oi" drawn out of the outer'ring l1 and the plungers 12 of the head part are moved outwardly untilthe endring will fity within-the encircling heads of the plunrers. 1 Theend .ringis then pla-eed in position within the encircling plungerheads, and the inner ring 10 lowered, so that the outer ends of theplungers enga-ge the track 15.

Pressure is then exerted on the inner ring to` force the `same down intothe outer ring. As the inner ring is forced down, the decreasingdiameter of the inclined track causes the plungers toflie forcedinwardly to contract the end ring.

A convenient way to force the inner ring down into the outer ring of thecontractingapparatus is to place the outer ring on the stationary baseof 'a power press and to exert pressure on the .inner ring by themovable plunger of the press.

Should a. power press having anupper ystationary piston and a movablebed plate supported by a plunger which /raisesthe y same beemployed,'the inner 'ringof the contracting apparatus would then be heldstationary while the outer ring would bevm'oved with respect thereto.

The winding described herein may, of

course, be ap lied to other'appliances than a rotor for t e .inventionis susceptible of other embodiments and adaptations than those set forthas illustrations.

The invention claimed is:

1. The method of making a rotor, which consists in placing a cylindricalcore'with longitudinal slots. into a cylindrical stamped metal windinghaving integral longitudinal conductors and end rings, and thencontracting said end rings perimetrically to insert said longitudinalconductors in said Aslots and hold them 4therein against radialdisplacement.

2. The method of making a. rotor, which consists in placing acylindrical corewith longitudinal slots into a cylindrical stam d metalwinding having integral longitudinal y conductors and endrings, and thenperimetrically contracting one of said end rings to insert saidlongitudinal'conductors in said slots and hold them therein againstradial displacement.

3. The method ofmaking a rotor, which consists in placing a cylindricalcore with longitudinal slots in a cylindrical stamped metal windinghaving integral longitudinal conductors and end rings, oneend ring beinglarger than theother and the longitudinal conductors near the smallerend ring being partially inserted in the longitudinal slots, and thenperimetrically contracting Athe larger end ring to entirely insert saidlongitudinal conductors in said slots.

4. A cylindrical winding for a rotor, llaving integral longitudinalconductors and end rings, the end rings being partially enclosed byrings which become non-magnetic as the temperature thereof. increases to'a critical point so as toincrease thefeiectlve conductivity -of saidend rings,

10 5. A cylindrical windingfor a rotor, liav ing integral lon litudinalconductors and end rings, the en 'ringsbeing partiallyenclosed by ringsof U-shaped cross-section which become non-magnet1c as the temperaturethereof increases to a critica-l point so as to increase tlieefectiveconductivity of vsaid end rings.

In .witness whereof, I have hereunto subscribed my name.

` JOHN M. BARR.

